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Rawat P, Boehning M, Hummel B, Aprile-Garcia F, Pandit AS, Eisenhardt N, Khavaran A, Niskanen E, Vos SM, Palvimo JJ, Pichler A, Cramer P, Sawarkar R. Stress-induced nuclear condensation of NELF drives transcriptional downregulation. Mol Cell 2021; 81:1013-1026.e11. [PMID: 33548202 PMCID: PMC7939545 DOI: 10.1016/j.molcel.2021.01.016] [Citation(s) in RCA: 75] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 10/20/2020] [Accepted: 01/11/2021] [Indexed: 12/21/2022]
Abstract
In response to stress, human cells coordinately downregulate transcription and translation of housekeeping genes. To downregulate transcription, the negative elongation factor (NELF) is recruited to gene promoters impairing RNA polymerase II elongation. Here we report that NELF rapidly forms nuclear condensates upon stress in human cells. Condensate formation requires NELF dephosphorylation and SUMOylation induced by stress. The intrinsically disordered region (IDR) in NELFA is necessary for nuclear NELF condensation and can be functionally replaced by the IDR of FUS or EWSR1 protein. We find that biomolecular condensation facilitates enhanced recruitment of NELF to promoters upon stress to drive transcriptional downregulation. Importantly, NELF condensation is required for cellular viability under stressful conditions. We propose that stress-induced NELF condensates reported here are nuclear counterparts of cytosolic stress granules. These two stress-inducible condensates may drive the coordinated downregulation of transcription and translation, likely forming a critical node of the stress survival strategy.
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Affiliation(s)
- Prashant Rawat
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Faculty of Biology, University of Freiburg, Freiburg, Germany; International Max Planck Research School for Molecular and Cellular Biology (IMPRS-MCB), Freiburg, Germany.
| | - Marc Boehning
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Barbara Hummel
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | | | - Anwit S Pandit
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; CIBSS, Centre for Integrative Biological Signaling Studies, Freiburg, Germany; Spemann Graduate School of Biology and Medicine, Albert Ludwigs University of Freiburg, Freiburg, Germany
| | - Nathalie Eisenhardt
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Ashkan Khavaran
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Einari Niskanen
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Seychelle M Vos
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Jorma J Palvimo
- Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
| | - Andrea Pichler
- Department of Epigenetics, Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany
| | - Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany.
| | - Ritwick Sawarkar
- Max Planck Institute of Immunobiology and Epigenetics, Freiburg, Germany; CIBSS, Centre for Integrative Biological Signaling Studies, Freiburg, Germany; MRC, University of Cambridge, Cambridge, UK.
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52
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Larke MSC, Schwessinger R, Nojima T, Telenius J, Beagrie RA, Downes DJ, Oudelaar AM, Truch J, Graham B, Bender MA, Proudfoot NJ, Higgs DR, Hughes JR. Enhancers predominantly regulate gene expression during differentiation via transcription initiation. Mol Cell 2021; 81:983-997.e7. [PMID: 33539786 PMCID: PMC7612206 DOI: 10.1016/j.molcel.2021.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 09/25/2020] [Accepted: 01/02/2021] [Indexed: 12/16/2022]
Abstract
Gene transcription occurs via a cycle of linked events, including initiation, promoter-proximal pausing, and elongation of RNA polymerase II (Pol II). A key question is how transcriptional enhancers influence these events to control gene expression. Here, we present an approach that evaluates the level and change in promoter-proximal transcription (initiation and pausing) in the context of differential gene expression, genome-wide. This combinatorial approach shows that in primary cells, control of gene expression during differentiation is achieved predominantly via changes in transcription initiation rather than via release of Pol II pausing. Using genetically engineered mouse models, deleted for functionally validated enhancers of the α- and β-globin loci, we confirm that these elements regulate Pol II recruitment and/or initiation to modulate gene expression. Together, our data show that gene expression during differentiation is regulated predominantly at the level of initiation and that enhancers are key effectors of this process.
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Affiliation(s)
- Martin S C Larke
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Ron Schwessinger
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Takayuki Nojima
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Jelena Telenius
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Robert A Beagrie
- Laboratory of Gene Regulation, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Damien J Downes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - A Marieke Oudelaar
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Julia Truch
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Bryony Graham
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - M A Bender
- Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Nicholas J Proudfoot
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, UK
| | - Douglas R Higgs
- Laboratory of Gene Regulation, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
| | - Jim R Hughes
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; MRC WIMM Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.
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53
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Dollinger R, Gilmour DS. Regulation of Promoter Proximal Pausing of RNA Polymerase II in Metazoans. J Mol Biol 2021; 433:166897. [PMID: 33640324 DOI: 10.1016/j.jmb.2021.166897] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/15/2021] [Accepted: 02/19/2021] [Indexed: 12/12/2022]
Abstract
Regulation of transcription is a tightly choreographed process. The establishment of RNA polymerase II promoter proximal pausing soon after transcription initiation and the release of Pol II into productive elongation are key regulatory processes that occur in early elongation. We describe the techniques and tools that have become available for the study of promoter proximal pausing and their utility for future experiments. We then provide an overview of the factors and interactions that govern a multipartite pausing process and address emerging questions surrounding the mechanism of RNA polymerase II's subsequent advancement into the gene body. Finally, we address remaining controversies and future areas of study.
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Affiliation(s)
- Roberta Dollinger
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 462 North Frear, University Park, PA 16802, USA.
| | - David S Gilmour
- Center for Eukaryotic Gene Regulation, Department of Biochemistry and Molecular Biology, The Pennsylvania State University, 465A North Frear, University Park, PA 16802, USA.
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54
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The XPB Subunit of the TFIIH Complex Plays a Critical Role in HIV-1 Transcription and XPB Inhibition by Spironolactone Prevents HIV-1 Reactivation from Latency. J Virol 2021; 95:JVI.01247-20. [PMID: 33239456 PMCID: PMC7851559 DOI: 10.1128/jvi.01247-20] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
HIV transcription requires assembly of cellular transcription factors at the HIV-1promoter. The TFIIH general transcription factor facilitates transcription initiation by opening the DNA strands around the transcription start site and phosphorylating the C-terminal domain for RNA polymerase II (RNAPII) for activation. Spironolactone (SP), an FDA approved aldosterone antagonist, triggers the proteasomal degradation of the XPB subunit of TFIIH, and concurrently suppresses acute HIV infection in vitro Here we investigated SP as a possible block-and-lock agent for a functional cure aimed at the transcriptional silencing of the viral reservoir. The long-term activity of SP was investigated in primary and cell line models of HIV-1 latency and reactivation. We show that SP rapidly inhibits HIV-1 transcription by reducing RNAPII recruitment to the HIV-1 genome. shRNA knockdown of XPB confirmed XPB degradation as the mechanism of action. Unfortunately, long-term pre-treatment with SP does not result in epigenetic suppression of HIV upon SP treatment interruption, since virus rapidly rebounds when XPB reemerges; however, SP alone without ART maintains the transcriptional suppression. Importantly, SP inhibits HIV reactivation from latency in both cell line models and resting CD4+T cells isolated from aviremic infected individuals upon cell stimulation with latency reversing agents. Furthermore, long-term treatment with concentrations of SP that potently degrade XPB does not lead to global dysregulation of cellular mRNA expression. Overall, these results suggest that XPB plays a key role in HIV transcriptional regulation and XPB degradation by SP strengthens the potential of HIV transcriptional inhibitors in block-and-lock HIV cure approaches.IMPORTANCE Antiretroviral therapy (ART) effectively reduces an individual's HIV loads to below the detection limit, nevertheless rapid viral rebound immediately ensues upon treatment interruption. Furthermore, virally suppressed individuals experience chronic immune activation from ongoing low-level virus expression. Thus, the importance of identifying novel therapeutics to explore in block-and-lock HIV functional cure approaches, aimed at the transcriptional and epigenetic silencing of the viral reservoir to block reactivation from latency. We investigated the potential of repurposing the FDA-approved spironolactone (SP), as one such drug. SP treatment rapidly degrades a host transcription factor subunit, XPB, inhibiting HIV transcription and blocking reactivation from latency. Long-term SP treatment does not affect cellular viability, cell cycle progression or global cellular transcription. SP alone blocks HIV transcription in the absence of ART but does not delay rebound upon drug removal as XPB rapidly reemerges. This study highlights XPB as a novel drug target in block-and-lock therapeutic approaches.
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55
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Noe Gonzalez M, Blears D, Svejstrup JQ. Causes and consequences of RNA polymerase II stalling during transcript elongation. Nat Rev Mol Cell Biol 2021; 22:3-21. [PMID: 33208928 DOI: 10.1038/s41580-020-00308-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2020] [Indexed: 02/07/2023]
Abstract
The journey of RNA polymerase II (Pol II) as it transcribes a gene is anything but a smooth ride. Transcript elongation is discontinuous and can be perturbed by intrinsic regulatory barriers, such as promoter-proximal pausing, nucleosomes, RNA secondary structures and the underlying DNA sequence. More substantial blocking of Pol II translocation can be caused by other physiological circumstances and extrinsic obstacles, including other transcribing polymerases, the replication machinery and several types of DNA damage, such as bulky lesions and DNA double-strand breaks. Although numerous different obstacles cause Pol II stalling or arrest, the cell somehow distinguishes between them and invokes different mechanisms to resolve each roadblock. Resolution of Pol II blocking can be as straightforward as temporary backtracking and transcription elongation factor S-II (TFIIS)-dependent RNA cleavage, or as drastic as premature transcription termination or degradation of polyubiquitylated Pol II and its associated nascent RNA. In this Review, we discuss the current knowledge of how these different Pol II stalling contexts are distinguished by the cell, how they overlap with each other, how they are resolved and how, when unresolved, they can cause genome instability.
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Affiliation(s)
- Melvin Noe Gonzalez
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Daniel Blears
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK.
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
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56
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Krasnopolsky S, Novikov A, Kuzmina A, Taube R. CRISPRi-mediated depletion of Spt4 and Spt5 reveals a role for DSIF in the control of HIV latency. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1864:194656. [PMID: 33333262 DOI: 10.1016/j.bbagrm.2020.194656] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 11/15/2020] [Accepted: 11/16/2020] [Indexed: 01/03/2023]
Abstract
Pivotal studies on the control of HIV transcription has laid the foundations for our understanding of how metazoan transcription is executed, and what are the factors that control this step. Part of this work established a role for DRB Sensitivity Inducing Factor (DSIF), consisting of Spt4 and Spt5, in promoting pause-release of RNA Polymerase II (Pol II) for optimal elongation. However, while there has been substantial progress in understanding the role of DSIF in mediating HIV gene transcription, its involvement in establishing viral latency has not been explored. Moreover, the effects of depleting Spt4 or Spt5, or simultaneously knocking down both subunits of DSIF have not been examined. In this study, we employed CRISPR interference (CRIPSRi) to knockdown the expression of Spt4, Spt5 or the entire DSIF complex, and monitored effects on HIV transcription and viral latency. Knocking down DSIF, or each of its subunits, inhibited HIV transcription, primarily at the step of Tat transactivation. This was accompanied by a decrease in promoter occupancy of Pol II and Cdk9, and to a lesser extent, AFF4. Interestingly, targeting the expression of one subunit of DSIF, reduced the protein stability of its counterpart partner. Moreover, depletion of Spt4, Spt5 or DSIF complex impaired cell growth, but did not cause cell death. Finally, knockdown of Spt4, Spt5 or DSIF, facilitated entry of HIV into latency. We conclude that each DSIF subunit plays a role in maintaining the stability of its other partner, achieving optimal function of the DSIF to enhance viral gene transcription.
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Affiliation(s)
- Simona Krasnopolsky
- The Shraga Segal Department of Microbiology Immunology and Genetics Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel
| | - Alex Novikov
- The Shraga Segal Department of Microbiology Immunology and Genetics Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel
| | - Alona Kuzmina
- The Shraga Segal Department of Microbiology Immunology and Genetics Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel
| | - Ran Taube
- The Shraga Segal Department of Microbiology Immunology and Genetics Faculty of Health Sciences, Ben-Gurion University of the Negev, Israel.
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57
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Tellier M, Zaborowska J, Caizzi L, Mohammad E, Velychko T, Schwalb B, Ferrer-Vicens I, Blears D, Nojima T, Cramer P, Murphy S. CDK12 globally stimulates RNA polymerase II transcription elongation and carboxyl-terminal domain phosphorylation. Nucleic Acids Res 2020; 48:7712-7727. [PMID: 32805052 PMCID: PMC7641311 DOI: 10.1093/nar/gkaa514] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/02/2020] [Accepted: 06/04/2020] [Indexed: 12/12/2022] Open
Abstract
Cyclin-dependent kinase 12 (CDK12) phosphorylates the carboxyl-terminal domain (CTD) of RNA polymerase II (pol II) but its roles in transcription beyond the expression of DNA damage response genes remain unclear. Here, we have used TT-seq and mNET-seq to monitor the direct effects of rapid CDK12 inhibition on transcription activity and CTD phosphorylation in human cells. CDK12 inhibition causes a genome-wide defect in transcription elongation and a global reduction of CTD Ser2 and Ser5 phosphorylation. The elongation defect is explained by the loss of the elongation factors LEO1 and CDC73, part of PAF1 complex, and SPT6 from the newly-elongating pol II. Our results indicate that CDK12 is a general activator of pol II transcription elongation and indicate that it targets both Ser2 and Ser5 residues of the pol II CTD.
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Affiliation(s)
- Michael Tellier
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Justyna Zaborowska
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Livia Caizzi
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Eusra Mohammad
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Taras Velychko
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Björn Schwalb
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Ivan Ferrer-Vicens
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Daniel Blears
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK
| | - Takayuki Nojima
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
| | - Patrick Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Am Fassberg 11, 37077 Göttingen, Germany
| | - Shona Murphy
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, UK
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58
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Nagarkar S, Wasnik R, Govada P, Cohen S, Shashidhara LS. Promoter Proximal Pausing Limits Tumorous Growth Induced by the Yki Transcription Factor in Drosophila. Genetics 2020; 216:67-77. [PMID: 32737120 PMCID: PMC7463282 DOI: 10.1534/genetics.120.303419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 07/27/2020] [Indexed: 12/15/2022] Open
Abstract
Promoter proximal pausing (PPP) of RNA polymerase II has emerged as a crucial rate-limiting step in the regulation of gene expression. Regulation of PPP is brought about by complexes 7SK snRNP, P-TEFb (Cdk9/cycT), and the negative elongation factor (NELF), which are highly conserved from Drosophila to humans. Here, we show that RNAi-mediated depletion of bin3 or Hexim of the 7SK snRNP complex or depletion of individual components of the NELF complex enhances Yki-driven growth, leading to neoplastic transformation of Drosophila wing imaginal discs. We also show that increased CDK9 expression cooperates with Yki in driving neoplastic growth. Interestingly, overexpression of CDK9 on its own or in the background of depletion of one of the components of 7SK snRNP or the NELF complex necessarily, and specifically, needed Yki overexpression to cause tumorous growth. Genome-wide gene expression analyses suggested that deregulation of protein homeostasis is associated with tumorous growth of wing imaginal discs. As both Fat/Hippo/Yki pathway and PPP are highly conserved, our observations may provide insights into mechanisms of oncogenic function of YAP-the ortholog of Yki in humans.
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Affiliation(s)
- Sanket Nagarkar
- Indian Institute of Science Education and Research (IISER), Pashan, Pune 411008
| | - Ruchi Wasnik
- Indian Institute of Science Education and Research (IISER), Pashan, Pune 411008
| | - Pravallika Govada
- Indian Institute of Science Education and Research (IISER), Pashan, Pune 411008
| | - Stephen Cohen
- Department of Cellular and Molecular Medicine, University of Copenhagen, 2200N, Denmark
| | - L S Shashidhara
- Indian Institute of Science Education and Research (IISER), Pashan, Pune 411008
- Ashoka University, Sonepat, Haryana 131029, India
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59
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Abstract
More than 30% of genes in higher eukaryotes are regulated by RNA polymerase II (Pol II) promoter proximal pausing. Pausing is released by the positive transcription elongation factor complex (P-TEFb). However, the exact mechanism by which this occurs and whether phosphorylation of the carboxyl-terminal domain of Pol II is involved in the process remains unknown. We previously reported that JMJD5 could generate tailless nucleosomes at position +1 from transcription start sites (TSS), thus perhaps enable progression of Pol II. Here we find that knockout of JMJD5 leads to accumulation of nucleosomes at position +1. Absence of JMJD5 also results in loss of or lowered transcription of a large number of genes. Interestingly, we found that phosphorylation, by CDK9, of Ser2 within two neighboring heptad repeats in the carboxyl-terminal domain of Pol II, together with phosphorylation of Ser5 within the second repeat, HR-Ser2p (1, 2)-Ser5p (2) for short, allows Pol II to bind JMJD5 via engagement of the N-terminal domain of JMJD5. We suggest that these events bring JMJD5 near the nucleosome at position +1, thus allowing JMJD5 to clip histones on this nucleosome, a phenomenon that may contribute to release of Pol II pausing.
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60
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Cramer P. Eukaryotic Transcription Turns 50. Cell 2020; 179:808-812. [PMID: 31675494 DOI: 10.1016/j.cell.2019.09.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 12/15/2022]
Abstract
This year we celebrate the 50th anniversary of the discovery of the three eukaryotic RNA polymerases. Ever since this seminal event in 1969, researchers have investigated the intricate mechanisms of gene transcription with great dedication. The transcription field continues to influence developmental, stem cell, and cancer biology.
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Affiliation(s)
- Patrick Cramer
- Department of Molecular Biology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
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61
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Thomas QA, Ard R, Liu J, Li B, Wang J, Pelechano V, Marquardt S. Transcript isoform sequencing reveals widespread promoter-proximal transcriptional termination in Arabidopsis. Nat Commun 2020; 11:2589. [PMID: 32444691 PMCID: PMC7244574 DOI: 10.1038/s41467-020-16390-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 04/29/2020] [Indexed: 01/22/2023] Open
Abstract
RNA polymerase II (RNAPII) transcription converts the DNA sequence of a single gene into multiple transcript isoforms that may carry alternative functions. Gene isoforms result from variable transcription start sites (TSSs) at the beginning and polyadenylation sites (PASs) at the end of transcripts. How alternative TSSs relate to variable PASs is poorly understood. Here, we identify both ends of RNA molecules in Arabidopsis thaliana by transcription isoform sequencing (TIF-seq) and report four transcript isoforms per expressed gene. While intragenic initiation represents a large source of regulated isoform diversity, we observe that ~14% of expressed genes generate relatively unstable short promoter-proximal RNAs (sppRNAs) from nascent transcript cleavage and polyadenylation shortly after initiation. The location of sppRNAs correlates with the position of promoter-proximal RNAPII stalling, indicating that large pools of promoter-stalled RNAPII may engage in transcriptional termination. We propose that promoter-proximal RNAPII stalling-linked to premature transcriptional termination may represent a checkpoint that governs plant gene expression.
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Affiliation(s)
- Quentin Angelo Thomas
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Ryan Ard
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Jinghan Liu
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
| | - Bingnan Li
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Jingwen Wang
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Vicent Pelechano
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - Sebastian Marquardt
- Copenhagen Plant Science Centre, Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.
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62
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Lyons DE, McMahon S, Ott M. A combinatorial view of old and new RNA polymerase II modifications. Transcription 2020; 11:66-82. [PMID: 32401151 DOI: 10.1080/21541264.2020.1762468] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The production of mRNA is a dynamic process that is highly regulated by reversible post-translational modifications of the C-terminal domain (CTD) of RNA polymerase II. The CTD is a highly repetitive domain consisting mostly of the consensus heptad sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7. Phosphorylation of serine residues within this repeat sequence is well studied, but modifications of all residues have been described. Here, we focus on integrating newly identified and lesser-studied CTD post-translational modifications into the existing framework. We also review the growing body of work demonstrating crosstalk between different CTD modifications and the functional consequences of such crosstalk on the dynamics of transcriptional regulation.
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Affiliation(s)
- Danielle E Lyons
- Gladstone Institute of Virology and Immunology, San Francisco, CA, USA
| | - Sarah McMahon
- Gladstone Institute of Virology and Immunology, San Francisco, CA, USA.,Department of Medicine, University of California, San Francisco , San Francisco, CA, USA
| | - Melanie Ott
- Gladstone Institute of Virology and Immunology, San Francisco, CA, USA.,Department of Medicine, University of California, San Francisco , San Francisco, CA, USA
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63
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Pham P, Malik S, Mak C, Calabrese PC, Roeder RG, Goodman MF. AID-RNA polymerase II transcription-dependent deamination of IgV DNA. Nucleic Acids Res 2020; 47:10815-10829. [PMID: 31566237 PMCID: PMC6846656 DOI: 10.1093/nar/gkz821] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 09/09/2019] [Accepted: 09/13/2019] [Indexed: 12/16/2022] Open
Abstract
Activation-induced deoxycytidine deaminase (AID) initiates somatic hypermutation (SHM) in immunoglobulin variable (IgV) genes to produce high-affinity antibodies. SHM requires IgV transcription by RNA polymerase II (Pol II). A eukaryotic transcription system including AID has not been reported previously. Here, we reconstitute AID-catalyzed deamination during Pol II transcription elongation in conjunction with DSIF transcription factor. C→T mutations occur at similar frequencies on non-transcribed strand (NTS) and transcribed strand (TS) DNA. In contrast, bacteriophage T7 Pol generates NTS mutations predominantly. AID-Pol II mutations are strongly favored in WRC and WGCW overlapping hot motifs (W = A or T, R = A or G) on both DNA strands. Single mutations occur on 70% of transcribed DNA clones. Mutations are correlated over a 15 nt distance in multiply mutated clones, suggesting that deaminations are catalyzed processively within a stalled or backtracked transcription bubble. Site-by-site comparisons for biochemical and human memory B-cell mutational spectra in an IGHV3-23*01 target show strongly favored deaminations occurring in the antigen-binding complementarity determining regions (CDR) compared to the framework regions (FW). By exhibiting consistency with B-cell SHM, our in vitro data suggest that biochemically defined reconstituted Pol II transcription systems can be used to investigate how, when and where AID is targeted.
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Affiliation(s)
- Phuong Pham
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Sohail Malik
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Chiho Mak
- Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
| | - Peter C Calabrese
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Myron F Goodman
- Department of Biological Sciences, University of Southern California, Los Angeles, CA 90089, USA.,Department of Chemistry, University of Southern California, Los Angeles, CA 90089, USA
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64
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Therapeutic Targeting of the General RNA Polymerase II Transcription Machinery. Int J Mol Sci 2020; 21:ijms21093354. [PMID: 32397434 PMCID: PMC7246882 DOI: 10.3390/ijms21093354] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/06/2020] [Accepted: 05/07/2020] [Indexed: 12/27/2022] Open
Abstract
Inhibitors targeting the general RNA polymerase II (RNAPII) transcription machinery are candidate therapeutics in cancer and other complex diseases. Here, we review the molecular targets and mechanisms of action of these compounds, framing them within the steps of RNAPII transcription. We discuss the effects of transcription inhibitors in vitro and in cellular models (with an emphasis on cancer), as well as their efficacy in preclinical and clinical studies. We also discuss the rationale for inhibiting broadly acting transcriptional regulators or RNAPII itself in complex diseases.
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65
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Basu S, Nandy A, Biswas D. Keeping RNA polymerase II on the run: Functions of MLL fusion partners in transcriptional regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194563. [PMID: 32348849 DOI: 10.1016/j.bbagrm.2020.194563] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 01/13/2020] [Accepted: 04/13/2020] [Indexed: 12/21/2022]
Abstract
Since the identification of key MLL fusion partners as transcription elongation factors regulating expression of HOX cluster genes during hematopoiesis, extensive work from the last decade has resulted in significant progress in our overall mechanistic understanding of role of MLL fusion partner proteins in transcriptional regulation of diverse set of genes beyond just the HOX cluster. In this review, we are going to detail overall understanding of role of MLL fusion partner proteins in transcriptional regulation and thus provide mechanistic insights into possible MLL fusion protein-mediated transcriptional misregulation leading to aberrant hematopoiesis and leukemogenesis.
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Affiliation(s)
- Subham Basu
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India
| | - Arijit Nandy
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Debabrata Biswas
- Laboratory of Transcription Biology, Molecular Genetics Division, CSIR-Indian Institute of Chemical Biology, 4, Raja S. C. Mullick Road, Kolkata 32, India.
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66
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Liu H, Lee S, Zhang Q, Chen Z, Zhang G. The potential underlying mechanism of the leukemia caused by MLL-fusion and potential treatments. Mol Carcinog 2020; 59:839-851. [PMID: 32329934 DOI: 10.1002/mc.23204] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 04/07/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022]
Abstract
A majority of infant and pediatric leukemias are caused by the mixed-lineage leukemia gene (MLL) fused with a variety of candidates. Several underlying mechanisms have been proposed. One currently popular view is that truncated MLL1 fusion and its associated complex constitutively hijacks super elongation complex, including positive transcription elongation factor b, CDK9, and cyclin T1 complex and DOT1L, to enhance the expression of transcription factors that maintain or restore stemness of leukocytes, as well as prevent the differentiation of hematopoietic progenitor cells. An alternative emerging view proposes that MLL1-fusion promotes the recruitment of TATA binding protein and RNA polymerase II (Pol II) initiation complex, so as to increase the expression levels of target genes. The fundamental mechanism of both theories are gain of function for truncated MLL1 fusions, either through Pol II elongation or initiation. Our recent progress in transcription regulation of paused Pol II through JMJD5, JMJD6, and JMJD7, combined with the repressive role of H3K4me3 revealed by others, prompted us to introduce a contrarian hypothesis: the failure to shut down transcribing units by MLL-fusions triggers the transformation: loss of function of truncated MLL1 fusions coupled with the loss of conversion of H3K4me1 to H3K4me3, leading to the constitutive expression of transcription factors that are in charge of maintenance of hematopoietic progenitor cells, may trigger the transformation of normal cells into cancer cells. Following this track, a potential treatment to eliminate these fusion proteins, which may ultimately cure the disease, is proposed.
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Affiliation(s)
- Haolin Liu
- Department of Biomedical Research, National Jewish Health, and Department of Immunology and Microbiology, Anschutz Medical Center, University of Colorado, Denver, Colorado
| | - Schuyler Lee
- Department of Biomedical Research, National Jewish Health, and Department of Immunology and Microbiology, Anschutz Medical Center, University of Colorado, Denver, Colorado
| | - Qianqian Zhang
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, Agriculture University, Beijing, China
| | - Zhongzhou Chen
- State Key Laboratory of Agrobiotechnology, College of Biological Sciences, Agriculture University, Beijing, China
| | - Gongyi Zhang
- Department of Biomedical Research, National Jewish Health, and Department of Immunology and Microbiology, Anschutz Medical Center, University of Colorado, Denver, Colorado
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67
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Aoi Y, Smith ER, Shah AP, Rendleman EJ, Marshall SA, Woodfin AR, Chen FX, Shiekhattar R, Shilatifard A. NELF Regulates a Promoter-Proximal Step Distinct from RNA Pol II Pause-Release. Mol Cell 2020; 78:261-274.e5. [PMID: 32155413 PMCID: PMC7402197 DOI: 10.1016/j.molcel.2020.02.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 12/17/2019] [Accepted: 02/18/2020] [Indexed: 02/08/2023]
Abstract
RNA polymerase II (RNA Pol II) is generally paused at promoter-proximal regions in most metazoans, and based on in vitro studies, this function has been attributed to the negative elongation factor (NELF). Here, we show that upon rapid depletion of NELF, RNA Pol II fails to be released into gene bodies, stopping instead around the +1 nucleosomal dyad-associated region. The transition to the 2nd pause region is independent of positive transcription elongation factor P-TEFb. During the heat shock response, RNA Pol II is rapidly released from pausing at heat shock-induced genes, while most genes are paused and transcriptionally downregulated. Both of these aspects of the heat shock response remain intact upon NELF loss. We find that NELF depletion results in global loss of cap-binding complex from chromatin without global reduction of nascent transcript 5' cap stability. Thus, our studies implicate NELF functioning in early elongation complexes distinct from RNA Pol II pause-release.
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Affiliation(s)
- Yuki Aoi
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Edwin R Smith
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Avani P Shah
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Emily J Rendleman
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Stacy A Marshall
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ashley R Woodfin
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Fei X Chen
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Ramin Shiekhattar
- Department of Human Genetics, Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Ali Shilatifard
- Simpson Querrey Center for Epigenetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA; Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
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68
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RNA Polymerase II Promoter-Proximal Pausing and Release to Elongation Are Key Steps Regulating Herpes Simplex Virus 1 Transcription. J Virol 2020; 94:JVI.02035-19. [PMID: 31826988 DOI: 10.1128/jvi.02035-19] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Accepted: 12/03/2019] [Indexed: 12/21/2022] Open
Abstract
Herpes simplex virus 1 (HSV-1) genes are transcribed by cellular RNA polymerase II (Pol II). Expression of viral immediate early (α) genes is followed sequentially by early (β), late (γ1), and true late (γ2) genes. We used precision nuclear run-on with deep sequencing to map and to quantify Pol II on the HSV-1(F) genome with single-nucleotide resolution. Approximately 30% of total Pol II relocated to viral genomes within 3 h postinfection (hpi), when it occupied genes of all temporal classes. At that time, Pol II on α genes accumulated most heavily at promoter-proximal pause (PPP) sites located ∼60 nucleotides downstream of the transcriptional start site, while β genes bore Pol II more evenly across gene bodies. At 6 hpi, Pol II increased on γ1 and γ2 genes while Pol II pausing remained prominent on α genes. At that time, average cytoplasmic mRNA expression from α and β genes decreased, relative to levels at 3 hpi, while γ1 relative expression increased slightly and γ2 expression increased more substantially. Cycloheximide treatment during the first 3 h reduced the amount of Pol II associated with the viral genome and confined most of the remaining Pol II to α gene PPP sites. Inhibition of both cyclin-dependent kinase 9 activity and viral DNA replication reduced Pol II on the viral genome and restricted much of the remaining Pol II to PPP sites.IMPORTANCE These data suggest that viral transcription is regulated not only by Pol II recruitment to viral genes but also by control of elongation into viral gene bodies. We provide a detailed map of Pol II occupancy on the HSV-1 genome that clarifies features of the viral transcriptome, including the first identification of Pol II PPP sites. The data indicate that Pol II is recruited to late genes early in infection. Comparing α and β gene occupancy at PPP sites and gene bodies suggests that Pol II is released more efficiently into the bodies of β genes than α genes at 3 hpi and that repression of α gene expression late in infection is mediated by prolonged promoter-proximal pausing. In addition, DNA replication is required to maintain full Pol II occupancy on viral DNA and to promote elongation on late genes later in infection.
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69
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P-TEFb as A Promising Therapeutic Target. Molecules 2020; 25:molecules25040838. [PMID: 32075058 PMCID: PMC7070488 DOI: 10.3390/molecules25040838] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 02/06/2020] [Accepted: 02/07/2020] [Indexed: 01/19/2023] Open
Abstract
The positive transcription elongation factor b (P-TEFb) was first identified as a general factor that stimulates transcription elongation by RNA polymerase II (RNAPII), but soon afterwards it turned out to be an essential cellular co-factor of human immunodeficiency virus (HIV) transcription mediated by viral Tat proteins. Studies on the mechanisms of Tat-dependent HIV transcription have led to radical advances in our knowledge regarding the mechanism of eukaryotic transcription, including the discoveries that P-TEFb-mediated elongation control of cellular transcription is a main regulatory step of gene expression in eukaryotes, and deregulation of P-TEFb activity plays critical roles in many human diseases and conditions in addition to HIV/AIDS. P-TEFb is now recognized as an attractive and promising therapeutic target for inflammation/autoimmune diseases, cardiac hypertrophy, cancer, infectious diseases, etc. In this review article, I will summarize our knowledge about basic P-TEFb functions, the regulatory mechanism of P-TEFb-dependent transcription, P-TEFb’s involvement in biological processes and diseases, and current approaches to manipulating P-TEFb functions for the treatment of these diseases.
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70
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Gregersen LH, Mitter R, Svejstrup JQ. Using TT chem-seq for profiling nascent transcription and measuring transcript elongation. Nat Protoc 2020; 15:604-627. [PMID: 31915390 DOI: 10.1038/s41596-019-0262-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Accepted: 10/29/2019] [Indexed: 01/08/2023]
Abstract
The dynamics of transcription can be studied genome wide by high-throughput sequencing of nascent and newly synthesized RNA. 4-thiouridine (4SU) labeling in vivo enables the specific capture of such new transcripts, with 4SU residues being tagged by biotin linkers and captured using streptavidin beads before library production and high-throughput sequencing. To achieve high-resolution profiles of transcribed regions, an RNA fragmentation step before biotin tagging was introduced, in an approach known as transient transcriptome sequencing (TT-seq). We recently introduced a chemical approach for RNA fragmentation that we refer to as TTchem-seq. We describe how TTchem-seq can be used in combination with transient inhibition of early elongation using the reversible CDK9 inhibitor, 5,6-dichlorobenzimidazole 1-β-D-ribofuranoside (DRB), to measure RNA polymerase II (RNAPII) elongation rates in vivo, a technique we call DRB/TTchem-seq. Here, we provide detailed protocols for carrying out TTchem-seq and DRB/TTchem-seq, including computational analysis. Experiments and data analysis can be performed over a period of 10-13 d and require molecular biology and bioinformatics skills.
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Affiliation(s)
- Lea H Gregersen
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK
| | - Richard Mitter
- Bioinformatics and Biostatistics, The Francis Crick Institute, London, UK
| | - Jesper Q Svejstrup
- Mechanisms of Transcription Laboratory, The Francis Crick Institute, London, UK.
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71
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H.S. Richter G, Hensel T, Schmidt O, Saratov V, von Heyking K, Becker-Dettling F, Prexler C, Yen HY, Steiger K, Fulda S, Dirksen U, Weichert W, Wang S, Burdach S, Schäfer BW. Combined Inhibition of Epigenetic Readers and Transcription Initiation Targets the EWS-ETS Transcriptional Program in Ewing Sarcoma. Cancers (Basel) 2020; 12:cancers12020304. [PMID: 32012890 PMCID: PMC7072515 DOI: 10.3390/cancers12020304] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/17/2020] [Accepted: 01/24/2020] [Indexed: 12/17/2022] Open
Abstract
Background: Previously, we used inhibitors blocking BET bromodomain binding proteins (BRDs) in Ewing sarcoma (EwS) and observed that long term treatment resulted in the development of resistance. Here, we analyze the possible interaction of BRD4 with cyclin-dependent kinase (CDK) 9. Methods: Co-immunoprecipitation experiments (CoIP) to characterize BRD4 interaction and functional consequences of inhibiting transcriptional elongation were assessed using drugs targeting of BRD4 or CDK9, either alone or in combination. Results: CoIP revealed an interaction of BRD4 with EWS-FLI1 and CDK9 in EwS. Treatment of EwS cells with CDKI-73, a specific CDK9 inhibitor (CDK9i), induced a rapid downregulation of EWS-FLI1 expression and block of contact-dependent growth. CDKI-73 induced apoptosis in EwS, as depicted by cleavage of Caspase 7 (CASP7), PARP and increased CASP3 activity, similar to JQ1. Microarray analysis following CDKI-73 treatment uncovered a transcriptional program that was only partially comparable to BRD inhibition. Strikingly, combined treatment of EwS with BRD- and CDK9-inhibitors re-sensitized cells, and was overall more effective than individual drugs not only in vitro but also in a preclinical mouse model in vivo. Conclusion: Treatment with BRD inhibitors in combination with CDK9i offers a new treatment option that significantly blocks the pathognomonic EWS-ETS transcriptional program and malignant phenotype of EwS.
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Affiliation(s)
- Günther H.S. Richter
- Children’s Cancer Research Centre and Department of Pediatrics, Klinikum rechts der Isar, Technische Universität München, 80804 München, Germany; (T.H.); (O.S.); (K.v.H.); (F.B.-D.); (C.P.); (S.B.)
- German Cancer Research Center (DKFZ), partner site Munich, 81377 Munich, Germany; (H.-Y.Y.); (W.W.)
- Division of Oncology and Hematology, Department of Pediatrics, Charité - Universitätsmedizin Berlin, 13353 Berlin, Germany
- Correspondence:
| | - Tim Hensel
- Children’s Cancer Research Centre and Department of Pediatrics, Klinikum rechts der Isar, Technische Universität München, 80804 München, Germany; (T.H.); (O.S.); (K.v.H.); (F.B.-D.); (C.P.); (S.B.)
- German Cancer Research Center (DKFZ), partner site Munich, 81377 Munich, Germany; (H.-Y.Y.); (W.W.)
| | - Oxana Schmidt
- Children’s Cancer Research Centre and Department of Pediatrics, Klinikum rechts der Isar, Technische Universität München, 80804 München, Germany; (T.H.); (O.S.); (K.v.H.); (F.B.-D.); (C.P.); (S.B.)
- German Cancer Research Center (DKFZ), partner site Munich, 81377 Munich, Germany; (H.-Y.Y.); (W.W.)
| | - Vadim Saratov
- Department of Oncology and Children’s Research Center, University Children’s Hospital, 8032 Zurich, Switzerland; (V.S.); (B.W.S.)
| | - Kristina von Heyking
- Children’s Cancer Research Centre and Department of Pediatrics, Klinikum rechts der Isar, Technische Universität München, 80804 München, Germany; (T.H.); (O.S.); (K.v.H.); (F.B.-D.); (C.P.); (S.B.)
- German Cancer Research Center (DKFZ), partner site Munich, 81377 Munich, Germany; (H.-Y.Y.); (W.W.)
| | - Fiona Becker-Dettling
- Children’s Cancer Research Centre and Department of Pediatrics, Klinikum rechts der Isar, Technische Universität München, 80804 München, Germany; (T.H.); (O.S.); (K.v.H.); (F.B.-D.); (C.P.); (S.B.)
| | - Carolin Prexler
- Children’s Cancer Research Centre and Department of Pediatrics, Klinikum rechts der Isar, Technische Universität München, 80804 München, Germany; (T.H.); (O.S.); (K.v.H.); (F.B.-D.); (C.P.); (S.B.)
- German Cancer Research Center (DKFZ), partner site Munich, 81377 Munich, Germany; (H.-Y.Y.); (W.W.)
| | - Hsi-Yu Yen
- German Cancer Research Center (DKFZ), partner site Munich, 81377 Munich, Germany; (H.-Y.Y.); (W.W.)
- Institute of Pathology, Technical University of Munich and Comparative Experimental Pathology (CEP), Technical University of Munich, 81675 Munich, Germany;
| | - Katja Steiger
- Institute of Pathology, Technical University of Munich and Comparative Experimental Pathology (CEP), Technical University of Munich, 81675 Munich, Germany;
| | - Simone Fulda
- Institute for Experimental Cancer Research in Paediatrics, Goethe-University Frankfurt, 60528 Frankfurt/Main, Germany;
| | - Uta Dirksen
- Pediatrics III, West German Cancer Centre, University Hospital of Essen, 45147 Essen, Germany;
- German Cancer Research Center (DKFZ), partner site Essen, 45147 Essen, Germany
| | - Wilko Weichert
- German Cancer Research Center (DKFZ), partner site Munich, 81377 Munich, Germany; (H.-Y.Y.); (W.W.)
- Institute of Pathology, Technical University of Munich and Comparative Experimental Pathology (CEP), Technical University of Munich, 81675 Munich, Germany;
| | - Shudong Wang
- Centre for Drug Discovery and Development and School of Pharmacy and Medical Sciences, University of South Australia Cancer Research Institute, Adelaide, South Australia 5001, Australia;
| | - Stefan Burdach
- Children’s Cancer Research Centre and Department of Pediatrics, Klinikum rechts der Isar, Technische Universität München, 80804 München, Germany; (T.H.); (O.S.); (K.v.H.); (F.B.-D.); (C.P.); (S.B.)
- German Cancer Research Center (DKFZ), partner site Munich, 81377 Munich, Germany; (H.-Y.Y.); (W.W.)
| | - Beat W. Schäfer
- Department of Oncology and Children’s Research Center, University Children’s Hospital, 8032 Zurich, Switzerland; (V.S.); (B.W.S.)
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Páhi ZG, Borsos BN, Pantazi V, Ujfaludi Z, Pankotai T. PARylation During Transcription: Insights into the Fine-Tuning Mechanism and Regulation. Cancers (Basel) 2020; 12:cancers12010183. [PMID: 31940791 PMCID: PMC7017041 DOI: 10.3390/cancers12010183] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 12/19/2019] [Accepted: 01/09/2020] [Indexed: 01/31/2023] Open
Abstract
Transcription is a multistep, tightly regulated process. During transcription initiation, promoter recognition and pre-initiation complex (PIC) formation take place, in which dynamic recruitment or exchange of transcription activators occur. The precise coordination of the recruitment and removal of transcription factors, as well as chromatin structural changes, are mediated by post-translational modifications (PTMs). Poly(ADP-ribose) polymerases (PARPs) are key players in this process, since they can modulate DNA-binding activities of specific transcription factors through poly-ADP-ribosylation (PARylation). PARylation can regulate the transcription at three different levels: (1) by directly affecting the recruitment of specific transcription factors, (2) by triggering chromatin structural changes during initiation and as a response to cellular stresses, or (3) by post-transcriptionally modulating the stability and degradation of specific mRNAs. In this review, we principally focus on these steps and summarise the recent findings, demonstrating the mechanisms through which PARylation plays a potential regulatory role during transcription and DNA repair.
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ITO T, HANDA H. Molecular mechanisms of thalidomide and its derivatives. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2020; 96:189-203. [PMID: 32522938 PMCID: PMC7298168 DOI: 10.2183/pjab.96.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Thalidomide, originally developed as a sedative drug, causes multiple defects due to severe teratogenicity, but it has been re-purposed for treating multiple myeloma, and derivatives such as lenalidomide and pomalidomide have been developed for treating blood cancers. Although the molecular mechanisms of thalidomide and its derivatives remained poorly understood until recently, we identified cereblon (CRBN), a primary direct target of thalidomide, using ferrite glycidyl methacrylate (FG) beads. CRBN is a ligand-dependent substrate receptor of the E3 ubiquitin ligase complex cullin-RING ligase 4 (CRL4CRBN). When a ligand such as thalidomide binds to CRBN, it recognizes various 'neosubstrates' depending on the shape of the ligand. CRL4CRBN binds many neosubstrates in the presence of various ligands. CRBN has been utilized in a novel protein knockdown technology named proteolysis targeting chimeras (PROTACs). Heterobifunctional molecules such as dBET1 are being developed to specifically degrade proteins of interest. Herein, we review recent advances in CRBN research.
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Affiliation(s)
- Takumi ITO
- Department of Chemical Biology, Tokyo Medical University, Tokyo, Japan
| | - Hiroshi HANDA
- Department of Chemical Biology, Tokyo Medical University, Tokyo, Japan
- Correspondence should be addressed: H. Handa, Department of Chemical Biology, Tokyo Medical University, 6-1-1 Shinjuku, Shinjuku-ku, Tokyo 160-8402, Japan (e-mail: )
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74
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Khan SZ, Gasperino S, Zeichner SL. Nuclear Transit and HIV LTR Binding of NF-κB Subunits Held by IκB Proteins: Implications for HIV-1 Activation. Viruses 2019; 11:v11121162. [PMID: 31888181 PMCID: PMC6949894 DOI: 10.3390/v11121162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 12/11/2019] [Indexed: 02/07/2023] Open
Abstract
No effective therapy to eliminate the HIV latently infected cell reservoir has been developed. One approach, “shock and kill”, employs agents that activate HIV, subsequently killing the activated infected cells and/or virus. Shock and kill requires agents that safely and effectively activate HIV. One class of activation agents works through classical NF-κB pathways, but global NF-κB activators are non-specific and toxic. There exist two major IκBs: IκBα, and IκBε, which hold activating NF-κB subunits in the cytoplasm, releasing them for nuclear transit upon cell stimulation. IκBα was considered the main IκB responsible for gene expression regulation, including HIV activation. IκBε is expressed in cells constituting much of the latent HIV reservoir, and IκBε knockout mice have a minimal phenotype, suggesting that IκBε could be a valuable target for HIV activation and reservoir depletion. We previously showed that targeting IκBε yields substantial increases in HIV expression. Here, we show that IκBε holds c-Rel and p65 activating NF-κB subunits in the cytoplasm, and that targeting IκBε with siRNA produces a strong increase in HIV expression associated with enhanced c-Rel and p65 transit to the nucleus and binding to the HIV LTR of the activating NF-κBs, demonstrating a mechanism through which targeting IκBε increases HIV expression. The findings suggest that it may be helpful to develop HIV activation approaches, acting specifically to target IκBε and its interactions with the NF-κBs.
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Affiliation(s)
- Sohrab Z. Khan
- Department of Pediatrics, Child Health Research Center, and the Pendleton Pediatric Infectious Disease Laboratory, University of Virginia, Charlottesville, VA 22908, USA; (S.Z.K.); (S.G.)
| | - Sofia Gasperino
- Department of Pediatrics, Child Health Research Center, and the Pendleton Pediatric Infectious Disease Laboratory, University of Virginia, Charlottesville, VA 22908, USA; (S.Z.K.); (S.G.)
| | - Steven L. Zeichner
- Department of Pediatrics, Child Health Research Center, and the Pendleton Pediatric Infectious Disease Laboratory, University of Virginia, Charlottesville, VA 22908, USA; (S.Z.K.); (S.G.)
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, VA 22908, USA
- Correspondence:
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75
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Tibes R, Bogenberger JM. Transcriptional Silencing of MCL-1 Through Cyclin-Dependent Kinase Inhibition in Acute Myeloid Leukemia. Front Oncol 2019; 9:1205. [PMID: 31921615 PMCID: PMC6920180 DOI: 10.3389/fonc.2019.01205] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 10/23/2019] [Indexed: 12/13/2022] Open
Abstract
Acute myeloid leukemia (AML) is the most common adult acute leukemia. Survival remains poor, despite decades of scientific advances. Cytotoxic induction chemotherapy regimens are standard-of-care for most patients. Many investigations have highlighted the genomic heterogeneity of AML, and several new targeted therapeutic options have recently been approved. Additional novel therapies are showing promising clinical results and may rapidly transform the therapeutic landscape of AML. Despite the emerging clinical success of B-cell lymphoma (BCL)-2 targeting in AML and a large body of preclinical data supporting myeloid leukemia cell (MCL)-1 as an attractive therapeutic target for AML, MCL-1 targeting remains relatively unexplored, although novel MCL-1 inhibitors are under clinical investigation. Inhibitors of cyclin-dependent kinases (CDKs) involved in the regulation of transcription, CDK9 in particular, are being investigated in AML as a strategy to target MCL-1 indirectly. In this article, we review the basis for CDK inhibition in oncology with a focus on relevant preclinical mechanism-of-action studies of CDK9 inhibitors in the context of their therapeutic potential specifically in AML.
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Affiliation(s)
- Raoul Tibes
- NYU School of Medicine & Perlmutter Cancer Center, NYU Langone Health, New York, NY, United States
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76
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Maita H, Nakagawa S. What is the switch for coupling transcription and splicing? RNA Polymerase II C‐terminal domain phosphorylation, phase separation and beyond. WILEY INTERDISCIPLINARY REVIEWS-RNA 2019; 11:e1574. [DOI: 10.1002/wrna.1574] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 01/12/2023]
Affiliation(s)
- Hiroshi Maita
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences Hokkaido University Sapporo Japan
| | - Shinichi Nakagawa
- RNA Biology Laboratory, Faculty of Pharmaceutical Sciences Hokkaido University Sapporo Japan
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77
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Wang X, Yu C, Wang C, Ma Y, Wang T, Li Y, Huang Z, Zhou M, Sun P, Zheng J, Yang S, Fan Y, Xiang R. Novel cyclin-dependent kinase 9 (CDK9) inhibitor with suppression of cancer stemness activity against non-small-cell lung cancer. Eur J Med Chem 2019; 181:111535. [DOI: 10.1016/j.ejmech.2019.07.038] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 01/16/2023]
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78
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Organization and regulation of gene transcription. Nature 2019; 573:45-54. [PMID: 31462772 DOI: 10.1038/s41586-019-1517-4] [Citation(s) in RCA: 367] [Impact Index Per Article: 73.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 07/30/2019] [Indexed: 12/18/2022]
Abstract
The regulated transcription of genes determines cell identity and function. Recent structural studies have elucidated mechanisms that govern the regulation of transcription by RNA polymerases during the initiation and elongation phases. Microscopy studies have revealed that transcription involves the condensation of factors in the cell nucleus. A model is emerging for the transcription of protein-coding genes in which distinct transient condensates form at gene promoters and in gene bodies to concentrate the factors required for transcription initiation and elongation, respectively. The transcribing enzyme RNA polymerase II may shuttle between these condensates in a phosphorylation-dependent manner. Molecular principles are being defined that rationalize transcriptional organization and regulation, and that will guide future investigations.
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79
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Chen FX, Smith ER, Shilatifard A. Born to run: control of transcription elongation by RNA polymerase II. Nat Rev Mol Cell Biol 2019; 19:464-478. [PMID: 29740129 DOI: 10.1038/s41580-018-0010-5] [Citation(s) in RCA: 262] [Impact Index Per Article: 52.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The dynamic regulation of transcription elongation by RNA polymerase II (Pol II) is an integral part of the implementation of gene expression programmes during development. In most metazoans, the majority of transcribed genes exhibit transient pausing of Pol II at promoter-proximal regions, and the release of Pol II into gene bodies is controlled by many regulatory factors that respond to environmental and developmental cues. Misregulation of the elongation stage of transcription is implicated in cancer and other human diseases, suggesting that mechanistic understanding of transcription elongation control is therapeutically relevant. In this Review, we discuss the features, establishment and maintenance of Pol II pausing, the transition into productive elongation, the control of transcription elongation by enhancers and by factors of other cellular processes, such as topoisomerases and poly(ADP-ribose) polymerases (PARPs), and the potential of therapeutic targeting of the elongation stage of transcription by Pol II.
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Affiliation(s)
- Fei Xavier Chen
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Edwin R Smith
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Ali Shilatifard
- Simpson Querrey Center for Epigenetics and the Department of Biochemistry and Molecular Genetics, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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80
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Etchegaray JP, Zhong L, Li C, Henriques T, Ablondi E, Nakadai T, Van Rechem C, Ferrer C, Ross KN, Choi JE, Samarakkody A, Ji F, Chang A, Sadreyev RI, Ramaswamy S, Nechaev S, Whetstine JR, Roeder RG, Adelman K, Goren A, Mostoslavsky R. The Histone Deacetylase SIRT6 Restrains Transcription Elongation via Promoter-Proximal Pausing. Mol Cell 2019; 75:683-699.e7. [PMID: 31399344 PMCID: PMC6907403 DOI: 10.1016/j.molcel.2019.06.034] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 04/11/2019] [Accepted: 06/24/2019] [Indexed: 12/19/2022]
Abstract
Transcriptional regulation in eukaryotes occurs at promoter-proximal regions wherein transcriptionally engaged RNA polymerase II (Pol II) pauses before proceeding toward productive elongation. The role of chromatin in pausing remains poorly understood. Here, we demonstrate that the histone deacetylase SIRT6 binds to Pol II and prevents the release of the negative elongation factor (NELF), thus stabilizing Pol II promoter-proximal pausing. Genetic depletion of SIRT6 or its chromatin deficiency upon glucose deprivation causes intragenic enrichment of acetylated histone H3 at lysines 9 (H3K9ac) and 56 (H3K56ac), activation of cyclin-dependent kinase 9 (CDK9)-that phosphorylates NELF and the carboxyl terminal domain of Pol II-and enrichment of the positive transcription elongation factors MYC, BRD4, PAF1, and the super elongation factors AFF4 and ELL2. These events lead to increased expression of genes involved in metabolism, protein synthesis, and embryonic development. Our results identified SIRT6 as a Pol II promoter-proximal pausing-dedicated histone deacetylase.
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Affiliation(s)
- Jean-Pierre Etchegaray
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA.
| | - Lei Zhong
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Catherine Li
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Telmo Henriques
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Eileen Ablondi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Tomoyoshi Nakadai
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Capucine Van Rechem
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Christina Ferrer
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Kenneth N Ross
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Jee-Eun Choi
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Ann Samarakkody
- University of North Dakota School of Medicine, Grand Forks, ND 58201, USA
| | - Fei Ji
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Andrew Chang
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Ruslan I Sadreyev
- Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Sridhar Ramaswamy
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Sergei Nechaev
- University of North Dakota School of Medicine, Grand Forks, ND 58201, USA
| | - Johnathan R Whetstine
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA
| | - Robert G Roeder
- Laboratory of Biochemistry and Molecular Biology, The Rockefeller University, New York, NY 10065, USA
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA
| | - Alon Goren
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
| | - Raul Mostoslavsky
- The Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, MA 02114, USA; The MGH Center for Regenerative Medicine, Harvard Medical School, Boston, MA 02114, USA; The Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA.
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81
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The hunt for RNA polymerase II elongation factors: a historical perspective. Nat Struct Mol Biol 2019; 26:771-776. [PMID: 31439940 DOI: 10.1038/s41594-019-0283-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Accepted: 07/18/2019] [Indexed: 02/07/2023]
Abstract
The discovery of the three eukaryotic nuclear RNA polymerases paved the way for serious biochemical investigations of eukaryotic transcription and the identification of eukaryotic transcription factors. Here we describe this adventure from our vantage point, with a focus on the hunt for factors that regulate elongation by RNA polymerase II.
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82
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Gressel S, Schwalb B, Cramer P. The pause-initiation limit restricts transcription activation in human cells. Nat Commun 2019; 10:3603. [PMID: 31399571 PMCID: PMC6689055 DOI: 10.1038/s41467-019-11536-8] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 07/18/2019] [Indexed: 01/01/2023] Open
Abstract
Eukaryotic gene transcription is often controlled at the level of RNA polymerase II (Pol II) pausing in the promoter-proximal region. Pausing Pol II limits the frequency of transcription initiation ('pause-initiation limit'), predicting that the pause duration must be decreased for transcriptional activation. To test this prediction, we conduct a genome-wide kinetic analysis of the heat shock response in human cells. We show that the pause-initiation limit restricts transcriptional activation at most genes. Gene activation generally requires the activity of the P-TEFb kinase CDK9, which decreases the duration of Pol II pausing and thereby enables an increase in the productive initiation frequency. The transcription of enhancer elements is generally not pause limited and can be activated without CDK9 activity. Our results define the kinetics of Pol II transcriptional regulation in human cells at all gene classes during a natural transcription response.
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Affiliation(s)
- Saskia Gressel
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany
| | - Björn Schwalb
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany.
| | - Patrick Cramer
- Department of Molecular Biology, Max-Planck-Institute for Biophysical Chemistry, Am Faßberg 11, 37077, Göttingen, Germany.
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83
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Bi X, Xu Y, Li T, Li X, Li W, Shao W, Wang K, Zhan G, Wu Z, Liu W, Lu JY, Wang L, Zhao J, Wu J, Na J, Li G, Li P, Shen X. RNA Targets Ribogenesis Factor WDR43 to Chromatin for Transcription and Pluripotency Control. Mol Cell 2019; 75:102-116.e9. [DOI: 10.1016/j.molcel.2019.05.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 01/09/2019] [Accepted: 04/16/2019] [Indexed: 11/30/2022]
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84
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Abstract
In this review, Core et al. discuss the recent advances in our understanding of the early steps in Pol II transcription, highlighting the events and factors involved in the establishment and release of paused Pol II. They also discuss a number of unanswered questions about the regulation and function of Pol II pausing. Precise spatio–temporal control of gene activity is essential for organismal development, growth, and survival in a changing environment. Decisive steps in gene regulation involve the pausing of RNA polymerase II (Pol II) in early elongation, and the controlled release of paused polymerase into productive RNA synthesis. Here we describe the factors that enable pausing and the events that trigger Pol II release into the gene. We also discuss open questions in the field concerning the stability of paused Pol II, nucleosomes as obstacles to elongation, and potential roles of pausing in defining the precision and dynamics of gene expression.
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Affiliation(s)
- Leighton Core
- Department of Molecular and Cell Biology, Institute of Systems Genomics, University of Connecticut, Storrs, Connecticut 06269, USA
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts 02115, USA
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85
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Hamdan FH, Johnsen SA. Perturbing Enhancer Activity in Cancer Therapy. Cancers (Basel) 2019; 11:cancers11050634. [PMID: 31067678 PMCID: PMC6563029 DOI: 10.3390/cancers11050634] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 04/26/2019] [Accepted: 05/05/2019] [Indexed: 02/07/2023] Open
Abstract
Tight regulation of gene transcription is essential for normal development, tissue homeostasis, and disease-free survival. Enhancers are distal regulatory elements in the genome that provide specificity to gene expression programs and are frequently misregulated in cancer. Recent studies examined various enhancer-driven malignant dependencies and identified different approaches to specifically target these programs. In this review, we describe numerous features that make enhancers good transcriptional targets in cancer therapy and discuss different approaches to overcome enhancer perturbation. Interestingly, a number of approved therapeutic agents, such as cyclosporine, steroid hormones, and thiazolidinediones, actually function by affecting enhancer landscapes by directly targeting very specific transcription factor programs. More recently, a broader approach to targeting deregulated enhancer programs has been achieved via Bromodomain and Extraterminal (BET) inhibition or perturbation of transcription-related cyclin-dependent kinases (CDK). One challenge to enhancer-targeted therapy is proper patient stratification. We suggest that monitoring of enhancer RNA (eRNA) expression may serve as a unique biomarker of enhancer activity that can help to predict and monitor responsiveness to enhancer-targeted therapies. A more thorough investigation of cancer-specific enhancers and the underlying mechanisms of deregulation will pave the road for an effective utilization of enhancer modulators in a precision oncology approach to cancer treatment.
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Affiliation(s)
- Feda H Hamdan
- Gene Regulatory Mechanisms and Molecular Epigenetics Lab, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA.
| | - Steven A Johnsen
- Gene Regulatory Mechanisms and Molecular Epigenetics Lab, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN 55905, USA.
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86
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Abstract
Recurrent chromosomal rearrangements leading to the generation of oncogenic fusion proteins are a common feature of many cancers. These aberrations are particularly prevalent in sarcomas and haematopoietic malignancies and frequently involve genes required for chromatin regulation and transcriptional control. In many cases, these fusion proteins are thought to be the primary driver of cancer development, altering chromatin dynamics to initiate oncogenic gene expression programmes. In recent years, mechanistic insights into the underlying molecular functions of a number of these oncogenic fusion proteins have been discovered. These insights have allowed the design of mechanistically anchored therapeutic approaches promising substantial treatment advances. In this Review, we discuss how our understanding of fusion protein function is informing therapeutic innovations and illuminating mechanisms of chromatin and transcriptional regulation in cancer and normal cells.
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Affiliation(s)
- Gerard L Brien
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland.
- Department of Pediatric Oncology, Dana Farber Cancer Institute and Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
| | - Kimberly Stegmaier
- Department of Pediatric Oncology, Dana Farber Cancer Institute and Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- The Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Scott A Armstrong
- Department of Pediatric Oncology, Dana Farber Cancer Institute and Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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87
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Mediouni S, Kessing CF, Jablonski JA, Thenin-Houssier S, Clementz M, Kovach MD, Mousseau G, de Vera IMS, Li C, Kojetin DJ, Evans DT, Valente ST. The Tat inhibitor didehydro-cortistatin A suppresses SIV replication and reactivation. FASEB J 2019; 33:8280-8293. [PMID: 31021670 DOI: 10.1096/fj.201801165r] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The HIV-1 transactivation protein (Tat) binds the HIV mRNA transactivation responsive element (TAR), regulating transcription and reactivation from latency. Drugs against Tat are unfortunately not clinically available. We reported that didehydro-cortistatin A (dCA) inhibits HIV-1 Tat activity. In human CD4+ T cells isolated from aviremic individuals and in the humanized mouse model of latency, combining dCA with antiretroviral therapy accelerates HIV-1 suppression and delays viral rebound upon treatment interruption. This drug class is amenable to block-and-lock functional cure approaches, aimed at a durable state of latency. Simian immunodeficiency virus (SIV) infection of rhesus macaques (RhMs) is the best-characterized model for AIDS research. Here, we demonstrate, using in vitro and cell-based assays, that dCA directly binds to SIV Tat's basic domain. dCA specifically inhibits SIV Tat binding to TAR, but not a Tat-Rev fusion protein, which activates transcription when Rev binds to its cognate RNA binding site replacing the apical region of TAR. Tat-TAR inhibition results in loss of RNA polymerase II recruitment to the SIV promoter. Importantly, dCA potently inhibits SIV reactivation from latently infected Hut78 cells and from primary CD4+ T cells explanted from SIVmac239-infected RhMs. In sum, dCA's remarkable breadth of activity encourages SIV-infected RhM use for dCA preclinical evaluation.-Mediouni, S., Kessing, C. F., Jablonski, J. A., Thenin-Houssier, S., Clementz, M., Kovach, M. D., Mousseau, G., de Vera, I.M.S., Li, C., Kojetin, D. J., Evans, D. T., Valente, S. T. The Tat inhibitor didehydro-cortistatin A suppresses SIV replication and reactivation.
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Affiliation(s)
- Sonia Mediouni
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Cari F Kessing
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Joseph A Jablonski
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Suzie Thenin-Houssier
- Institute of Human Genetics (IGH), CNRS-University of Montpelier, Montpelier, France
| | - Mark Clementz
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Melia D Kovach
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Guillaume Mousseau
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Ian Mitchelle S de Vera
- Department of Pharmacology and Physiology, St. Louis University School of Medicine, St. Louis, Missouri, USA
| | - Chuan Li
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, Florida, USA
| | - Douglas J Kojetin
- Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, Florida, USA
| | - David T Evans
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Susana T Valente
- Department of Immunology and Microbiology, The Scripps Research Institute, Jupiter, Florida, USA
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88
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Mitra P, Deshmukh AS, Gurupwar R, Kashyap P. Characterization of Toxoplasma gondii Spt5 like transcription elongation factor. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:184-197. [DOI: 10.1016/j.bbagrm.2019.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/26/2018] [Accepted: 01/06/2019] [Indexed: 12/14/2022]
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89
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Promoter-proximal pausing mediated by the exon junction complex regulates splicing. Nat Commun 2019; 10:521. [PMID: 30705266 PMCID: PMC6355915 DOI: 10.1038/s41467-019-08381-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 01/04/2019] [Indexed: 02/08/2023] Open
Abstract
Promoter-proximal pausing of RNA polymerase II (Pol II) is a widespread transcriptional regulatory step across metazoans. Here we find that the nuclear exon junction complex (pre-EJC) is a critical and conserved regulator of this process. Depletion of pre-EJC subunits leads to a global decrease in Pol II pausing and to premature entry into elongation. This effect occurs, at least in part, via non-canonical recruitment of pre-EJC components at promoters. Failure to recruit the pre-EJC at promoters results in increased binding of the positive transcription elongation complex (P-TEFb) and in enhanced Pol II release. Notably, restoring pausing is sufficient to rescue exon skipping and the photoreceptor differentiation defect associated with depletion of pre-EJC components in vivo. We propose that the pre-EJC serves as an early transcriptional checkpoint to prevent premature entry into elongation, ensuring proper recruitment of RNA processing components that are necessary for exon definition.
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90
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Luo Q, Deng W, Wang H, Fan H, Zhang J. BRD4 interacts with PML/RARα in acute promyelocytic leukemia. Front Med 2018; 12:726-734. [PMID: 30552662 DOI: 10.1007/s11684-017-0604-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 10/24/2017] [Indexed: 11/24/2022]
Abstract
Bromodomain-containing 4 (BRD4) has been considered as an important requirement for disease maintenance and an attractive therapeutic target for cancer therapy. This protein can be targeted by JQ1, a selective small-molecule inhibitor. However, few studies have investigated whether BRD4 influenced acute promyelocytic leukemia (APL), and whether BRD4 had interaction with promyelocytic leukemia-retinoic acid receptor α (PML/RARα) fusion protein to some extent. Results from cell viability assay, cell cycle analysis, and Annexin-V/PI analysis indicated that JQ1 inhibited the growth of NB4 cells, an APL-derived cell line, and induced NB4 cell cycle arrest at G1 and apoptosis. Then, we used co-immunoprecipitation (co-IP) assay and immunoblot to demonstrate the endogenous interaction of BRD4 and PML/RARα in NB4 cells. Moreover, downregulation of PML/RARα at the mRNA and protein levels was observed upon JQ1 treatment. Furthermore, results from the RT-qPCR, ChIP-qPCR, and re-ChIP-qPCR assays showed that BRD4 and PML/RARα co-existed on the same regulatory regions of their target genes. Hence, we showed a new discovery of the interaction of BRD4 and PML/RARα, as well as the decline of PML/RARα expression, under JQ1 treatment.
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Affiliation(s)
- Qun Luo
- State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Wanglong Deng
- State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Haiwei Wang
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences, Shanghai, 200025, China
| | - Huiyong Fan
- State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Ji Zhang
- State Key Laboratory of Medical Genomics, Ruijin Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
- Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences, Shanghai, 200025, China.
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91
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Sharma P, Lioutas A, Fernandez-Fuentes N, Quilez J, Carbonell-Caballero J, Wright RHG, Di Vona C, Le Dily F, Schüller R, Eick D, Oliva B, Beato M. Arginine Citrullination at the C-Terminal Domain Controls RNA Polymerase II Transcription. Mol Cell 2018; 73:84-96.e7. [PMID: 30472187 DOI: 10.1016/j.molcel.2018.10.016] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/31/2018] [Accepted: 10/09/2018] [Indexed: 12/21/2022]
Abstract
The post-translational modification of key residues at the C-terminal domain of RNA polymerase II (RNAP2-CTD) coordinates transcription, splicing, and RNA processing by modulating its capacity to act as a landing platform for a variety of protein complexes. Here, we identify a new modification at the CTD, the deimination of arginine and its conversion to citrulline by peptidyl arginine deiminase 2 (PADI2), an enzyme that has been associated with several diseases, including cancer. We show that, among PADI family members, only PADI2 citrullinates R1810 (Cit1810) at repeat 31 of the CTD. Depletion of PADI2 or loss of R1810 results in accumulation of RNAP2 at transcription start sites, reduced gene expression, and inhibition of cell proliferation. Cit1810 is needed for interaction with the P-TEFb (positive transcription elongation factor b) kinase complex and for its recruitment to chromatin. In this way, CTD-Cit1810 favors RNAP2 pause release and efficient transcription in breast cancer cells.
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Affiliation(s)
- Priyanka Sharma
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - Antonios Lioutas
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - Narcis Fernandez-Fuentes
- IBERS, Institute of Biological, Environmental and Rural Science, Aberystwyth University, Aberystwyth SY23 3EB, UK
| | - Javier Quilez
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - José Carbonell-Caballero
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - Roni H G Wright
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - Chiara Di Vona
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - François Le Dily
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain
| | - Roland Schüller
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center of Integrated Protein Science, Munich, Germany
| | - Dirk Eick
- Department of Molecular Epigenetics, Helmholtz Center Munich, Center of Integrated Protein Science, Munich, Germany
| | - Baldomero Oliva
- Universitat Pompeu Fabra (UPF), Barcelona, Spain; Structural Bioinformatics Laboratory (GRIB-IMIM), Department of Experimental and Health Sciences, Barcelona 08003, Spain
| | - Miguel Beato
- Gene Regulation, Stem Cells and Cancer Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology (BIST), Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain.
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92
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Abstract
The fact that many cancer types display transcriptional addiction driven by dysregulation of oncogenic enhancers and transcription factors has led to increased interest in a group of protein kinases, known as transcriptional cyclin dependent kinases (tCDKs), as potential therapeutic targets. Despite early reservations about targeting a process that is essential to healthy cell types, there is now evidence that targeting tCDKs could provide enough therapeutic window to be effective in the clinic. Here, we discuss recent developments in this field, with an emphasis on highly-selective inhibitors and the challenges to be addressed before these inhibitors could be used for therapeutic purposes. Abbreviations: CAK: CDK-activating kinase;CDK: cyclin-dependent kinase;CMGC group: CDK-, MAPK-, GSK3-, and CLK-like;CTD: C-terminal repeat domain of the RPB1 subunit of RNA polymerase II;DRB: 5,6-dichloro-1-β-D-ribofuranosylbenzimidazole;mCRPC: metastatic castration-resistant prostate cancer;NSCLC: non-small cell lung cancer;P-TEFb: positive elongation factor b;RNAPII: RNA polymerase II;S2: serine-2 of CTD repeats;S5: serine-5 of CTD repeats;S7: serine-7 of CTD repeats;SEC: super elongation complex;tCDK: transcriptional cyclin-dependent kinase;TNBC: triple-negative breast cancer
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Affiliation(s)
- Matthew D Galbraith
- a Linda Crnic Institute for Down Syndrome, School of Medicine , University of Colorado Anschutz Medical Campus , Aurora , CO , USA.,b Department of Pharmacology, School of Medicine , University of Colorado Anschutz Medical Campus , Aurora , CO , USA
| | - Heather Bender
- a Linda Crnic Institute for Down Syndrome, School of Medicine , University of Colorado Anschutz Medical Campus , Aurora , CO , USA.,b Department of Pharmacology, School of Medicine , University of Colorado Anschutz Medical Campus , Aurora , CO , USA
| | - Joaquín M Espinosa
- a Linda Crnic Institute for Down Syndrome, School of Medicine , University of Colorado Anschutz Medical Campus , Aurora , CO , USA.,b Department of Pharmacology, School of Medicine , University of Colorado Anschutz Medical Campus , Aurora , CO , USA.,c Department of Molecular, Cellular and Developmental Biology , University of Colorado Boulder , Boulder , CO , USA
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93
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Abstract
Cyclin-dependent kinase 9 (CDK9) is critical for RNA Polymerase II (Pol II) transcription initiation, elongation, and termination in several key biological processes including development, differentiation, and cell fate responses. A broad range of diseases are characterized by CDK9 malfunction, illustrating its importance in maintaining transcriptional homeostasis in basal- and signal-regulated conditions. Here we provide a historical recount of CDK9 discovery and the current models suggesting CDK9 is a central hub necessary for proper execution of different steps in the transcription cycle. Finally, we discuss the current therapeutic strategies to treat CDK9 malfunction in several disease states. Abbreviations: CDK: Cyclin-dependent kinase; Pol II: RNA Polymerase II; PIC: Pre-initiation Complex; TFIIH: Transcription Factor-II H; snoRNA: small nucleolar RNA; CycT: CyclinT1/T2; P-TEFb: Positive Transcription Elongation Factor Complex; snRNP: small nuclear ribonucleo-protein; HEXIM: Hexamethylene Bis-acetamide-inducible Protein 1/2; LARP7: La-related Protein 7; MePCE: Methylphosphate Capping Enzyme; HIV: human immunodeficiency virus; TAT: trans-activator of transcription; TAR: Trans-activation response element; Hsp70: Heat Shock Protein 70; Hsp90/Cdc37: Hsp90- Hsp90 co-chaperone Cdc37; DSIF: DRB Sensitivity Inducing Factor; NELF: Negative Elongation Factor; CPSF: cleavage and polyadenylation-specific factor; CSTF: cleavage-stimulatory factor; eRNA: enhancer RNA; BRD4: Bromodomain-containing protein 4; JMJD6: Jumonji C-domain-containing protein 6; SEC: Super Elongation Complex; ELL: eleven-nineteen Lys-rich leukemia; ENL: eleven-nineteen leukemia; MLL: mixed lineage leukemia; BEC: BRD4-containing Elongation Complex; SEC-L2/L3: SEC-like complexes; KAP1: Kruppel-associated box-protein 1; KEC: KAP1-7SK Elongation Complex; DRB: Dichloro-1-ß-D-Ribofuranosylbenzimidazole; H2Bub1: H2B mono-ubiquitination; KM: KM05382; PP1: Protein Phosphatase 1; CDK9i: CDK9 inhibitor; SHAPE: Selective 2'-hydroxyl acylation analyzed by primer extension; TE: Typical enhancer; SE : Super enhancer.
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Affiliation(s)
- Curtis W Bacon
- a Biological Chemistry Graduate Program , The University of Texas Southwestern Medical Center , Dallas, TX , USA
| | - Iván D'Orso
- b Department of Microbiology , The University of Texas Southwestern Medical Center , Dallas , TX , USA
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94
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Furlan A, Agbazahou F, Henry M, Gonzalez-Pisfil M, Le Nézet C, Champelovier D, Fournier M, Vandenbunder B, Bidaux G, Héliot L. P-TEFb et Brd4. Med Sci (Paris) 2018; 34:685-692. [DOI: 10.1051/medsci/20183408015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
La physiologie d’une cellule est dictée par l’intégration des signaux qu’elle reçoit et la mise en place de réponses adaptées par le biais, entre autres, de programmes transcriptionnels adéquats. Pour assurer un contrôle optimal de ces réponses, des mécanismes de régulation ont été sélectionnés, dont un processus de pause transcriptionnelle et de levée de cette pause par P-TEFb (positive transcription elongation factor) et Brd4 (bromodomain-containing protein 4). Le dérèglement de ce processus peut conduire à l’apparition de pathologies. P-TEFb et Brd4 ont ainsi émergé au cours des dernières années comme des cibles thérapeutiques potentielles dans le cadre des cancers et du syndrome d‘immunodéficience acquise (sida) notamment.
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95
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Erickson B, Sheridan RM, Cortazar M, Bentley DL. Dynamic turnover of paused Pol II complexes at human promoters. Genes Dev 2018; 32:1215-1225. [PMID: 30150253 PMCID: PMC6120720 DOI: 10.1101/gad.316810.118] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/11/2018] [Indexed: 12/30/2022]
Abstract
Paused RNA polymerase II (Pol II) that piles up near most human promoters is the target of mechanisms that control entry into productive elongation. Whether paused Pol II is a stable or dynamic target remains unresolved. We report that most 5' paused Pol II throughout the genome is turned over within 2 min. This process is revealed under hypertonic conditions that prevent Pol II recruitment to promoters. This turnover requires cell viability but is not prevented by inhibiting transcription elongation, suggesting that it is mediated at the level of termination. When initiation was prevented by triptolide during recovery from high salt, a novel preinitiated state of Pol II lacking the pausing factor Spt5 accumulated at transcription start sites. We propose that Pol II occupancy near 5' ends is governed by a cycle of ongoing assembly of preinitiated complexes that transition to pause sites followed by eviction from the DNA template. This model suggests that mechanisms regulating the transition to productive elongation at pause sites operate on a dynamic population of Pol II that is turning over at rates far higher than previously suspected. We suggest that a plausible alternative to elongation control via escape from a stable pause is by escape from premature termination.
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Affiliation(s)
- Benjamin Erickson
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Ryan M Sheridan
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Michael Cortazar
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - David L Bentley
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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96
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Structure of activated transcription complex Pol II-DSIF-PAF-SPT6. Nature 2018; 560:607-612. [PMID: 30135578 DOI: 10.1038/s41586-018-0440-4] [Citation(s) in RCA: 268] [Impact Index Per Article: 44.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/17/2018] [Indexed: 11/09/2022]
Abstract
Gene regulation involves activation of RNA polymerase II (Pol II) that is paused and bound by the protein complexes DRB sensitivity-inducing factor (DSIF) and negative elongation factor (NELF). Here we show that formation of an activated Pol II elongation complex in vitro requires the kinase function of the positive transcription elongation factor b (P-TEFb) and the elongation factors PAF1 complex (PAF) and SPT6. The cryo-EM structure of an activated elongation complex of Sus scrofa Pol II and Homo sapiens DSIF, PAF and SPT6 was determined at 3.1 Å resolution and compared to the structure of the paused elongation complex formed by Pol II, DSIF and NELF. PAF displaces NELF from the Pol II funnel for pause release. P-TEFb phosphorylates the Pol II linker to the C-terminal domain. SPT6 binds to the phosphorylated C-terminal-domain linker and opens the RNA clamp formed by DSIF. These results provide the molecular basis for Pol II pause release and elongation activation.
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97
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Vos SM, Farnung L, Urlaub H, Cramer P. Structure of paused transcription complex Pol II-DSIF-NELF. Nature 2018; 560:601-606. [PMID: 30135580 PMCID: PMC6245578 DOI: 10.1038/s41586-018-0442-2] [Citation(s) in RCA: 240] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Accepted: 07/17/2018] [Indexed: 11/24/2022]
Abstract
Metazoan gene regulation often involves the pausing of RNA polymerase II (Pol II) in the promoter-proximal region. Paused Pol II is stabilized by the protein complexes DRB sensitivity-inducing factor (DSIF) and negative elongation factor (NELF). Here we report the cryo-electron microscopy structure of a paused transcription elongation complex containing Sus scrofa Pol II and Homo sapiens DSIF and NELF at 3.2 Å resolution. The structure reveals a tilted DNA-RNA hybrid that impairs binding of the nucleoside triphosphate substrate. NELF binds the polymerase funnel, bridges two mobile polymerase modules, and contacts the trigger loop, thereby restraining Pol II mobility that is required for pause release. NELF prevents binding of the anti-pausing transcription elongation factor IIS (TFIIS). Additionally, NELF possesses two flexible 'tentacles' that can contact DSIF and exiting RNA. These results define the paused state of Pol II and provide the molecular basis for understanding the function of NELF during promoter-proximal gene regulation.
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Affiliation(s)
- Seychelle M Vos
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen, Germany
| | - Lucas Farnung
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen, Germany
| | - Henning Urlaub
- Max Planck Institute for Biophysical Chemistry, Bioanalytical Mass Spectrometry, Göttingen, Germany
- University Medical Center Göttingen, Institute of Clinical Chemistry, Bioanalytics Group, Göttingen, Germany
| | - Patrick Cramer
- Max Planck Institute for Biophysical Chemistry, Department of Molecular Biology, Göttingen, Germany.
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98
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Abstract
BACKGROUND The viral transactivator Tat protein is a key modulator of HIV-1 replication, as it regulates transcriptional elongation from the integrated proviral genome. Tat recruits the human transcription elongation factor b, and other host proteins, such as the super elongation complex, to activate the cellular RNA polymerase II, normally stalled shortly after transcription initiation at the HIV promoter. By means of a complex set of interactions with host cellular factors, Tat determines the fate of viral activity within the infected cell. The virus will either actively replicate to promote dissemination in blood and tissues, or become dormant mostly in memory CD4+ T cells, as part of a small but long-living latent reservoir, the main obstacle for HIV eradication. OBJECTIVE In this review, we summarize recent advances in the understanding of the multi-step mechanism that regulates Tat-mediated HIV-1 transcription and RNA polymerase II release, to promote viral transcription elongation. Early events of the human transcription elongation factor b release from the inhibitory 7SK small nuclear ribonucleoprotein complex and its recruitment to the HIV promoter will be discussed. Specific roles of the super elongation complex subunits during transcription elongation, and insight on recently identified cellular factors and mechanisms regulating HIV latency will be detailed. CONCLUSION Understanding the complexity of HIV transcriptional regulation by host factors may open the door for development of novel strategies to eradicate the resilient latent reservoir.
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Affiliation(s)
- Guillaume Mousseau
- The Scripps Research Institute, Department of Immunology and Microbiology, 130 Scripps Way, Jupiter, FL 33458. United States
| | - Susana T Valente
- The Scripps Research Institute, Department of Immunology and Microbiology, 130 Scripps Way, Jupiter, FL 33458. United States
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99
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Faust TB, Li Y, Bacon CW, Jang GM, Weiss A, Jayaraman B, Newton BW, Krogan NJ, D'Orso I, Frankel AD. The HIV-1 Tat protein recruits a ubiquitin ligase to reorganize the 7SK snRNP for transcriptional activation. eLife 2018; 7:31879. [PMID: 29845934 PMCID: PMC5999396 DOI: 10.7554/elife.31879] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 05/26/2018] [Indexed: 12/12/2022] Open
Abstract
The HIV-1 Tat protein hijacks P-TEFb kinase to activate paused RNA polymerase II (RNAP II) at the viral promoter. Tat binds additional host factors, but it is unclear how they regulate RNAP II elongation. Here, we identify the cytoplasmic ubiquitin ligase UBE2O as critical for Tat transcriptional activity. Tat hijacks UBE2O to ubiquitinate the P-TEFb kinase inhibitor HEXIM1 of the 7SK snRNP, a fraction of which also resides in the cytoplasm bound to P-TEFb. HEXIM1 ubiquitination sequesters it in the cytoplasm and releases P-TEFb from the inhibitory 7SK complex. Free P-TEFb then becomes enriched in chromatin, a process that is also stimulated by treating cells with a CDK9 inhibitor. Finally, we demonstrate that UBE2O is critical for P-TEFb recruitment to the HIV-1 promoter. Together, the data support a unique model of elongation control where non-degradative ubiquitination of nuclear and cytoplasmic 7SK snRNP pools increases P-TEFb levels for transcriptional activation.
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Affiliation(s)
- Tyler B Faust
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Yang Li
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Curtis W Bacon
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Gwendolyn M Jang
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,J David Gladstone Institutes, San Francisco, United States
| | - Amit Weiss
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Bhargavi Jayaraman
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
| | - Billy W Newton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,J David Gladstone Institutes, San Francisco, United States
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States.,J David Gladstone Institutes, San Francisco, United States
| | - Iván D'Orso
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, United States
| | - Alan D Frankel
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, United States
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100
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Nikolaou KC, Moulos P, Harokopos V, Chalepakis G, Talianidis I. Kmt5a Controls Hepatic Metabolic Pathways by Facilitating RNA Pol II Release from Promoter-Proximal Regions. Cell Rep 2018; 20:909-922. [PMID: 28746875 PMCID: PMC5542855 DOI: 10.1016/j.celrep.2017.07.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 06/23/2017] [Accepted: 06/30/2017] [Indexed: 01/02/2023] Open
Abstract
H4K20 monomethylation maintains genome integrity by regulating proper mitotic condensation, DNA damage response, and replication licensing. Here, we show that, in non-dividing hepatic cells, H4K20Me1 is specifically enriched in active gene bodies and dynamically regulated by the antagonistic action of Kmt5a methylase and Kdm7b demethylase. In liver-specific Kmt5a-deficient mice, reduced levels of H4K20Me1 correlated with reduced RNA Pol II release from promoter-proximal regions. Genes regulating glucose and fatty acid metabolism were most sensitive to impairment of RNA Pol II release. Downregulation of glycolytic genes resulted in an energy starvation condition partially compensated by AMP-activated protein kinase (AMPK) activation and increased mitochondrial activity. This metabolic reprogramming generated a highly sensitized state that, upon different metabolic stress conditions, quickly aggravated into a senescent phenotype due to ROS overproduction-mediated oxidative DNA damage. The results illustrate how defects in the general process of RNA Pol II transition into a productive elongation phase can trigger specific metabolic changes and genome instability. H4K20Me1 is dynamically deposited in the gene bodies of active genes Kmt5a regulates RNA Pol II release from promoter-proximal pause sites Kmt5a regulates metabolic gene transcription The transcription regulatory function of Kmt5a is important for genome integrity
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Affiliation(s)
- Kostas C Nikolaou
- Biomedical Sciences Research Center Alexander Fleming, 16672 Vari, Greece
| | - Panagiotis Moulos
- Biomedical Sciences Research Center Alexander Fleming, 16672 Vari, Greece
| | - Vangelis Harokopos
- Biomedical Sciences Research Center Alexander Fleming, 16672 Vari, Greece
| | - George Chalepakis
- Department of Biology, University of Crete, 71110 Herakleion, Crete, Greece
| | - Iannis Talianidis
- Biomedical Sciences Research Center Alexander Fleming, 16672 Vari, Greece; Institute of Molecular Biology and Biotechnology, FORTH, 70013 Herakleion, Crete, Greece.
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